Method and apparatus for continuous vacuum metal coating of metal strip



Sept. 7, 1965 R. M. BRICK ETAL METHOD AND APPARATUS FOR CONTINUOUS.ACUUM METAL COATING OF METAL STRIP 2 Sheets-Sheet l Filed Feb. 4, 1960Sept 7, 1965 R. M. BRICK ETAL 3,205,086

METHOD AND APPARATUS FOR CONTINUOUS VACUUM METAL COATING OF METAL STRIPFiled Feb. 4, 1960 2 Sheets-Sheet 2 United States Patent O '3,205,086METHOD A'ND APPARATUS FOR CONTINUOUS VACUUM METAL COATING '0F NETALSTRIP Robert M. Brick, Hinsdale, and Curtis E. Maier, Riverside, Ill.,assignors t Continental Can Company, Inc.,

New York, N .Y., a corporation of New Yori:

Filed Feb. 4, 1960, Ser. No. 6,674 v 24 Claims. (Cl. 117-14) Thisinvention relates to the application o-f coatings on strip and sheetmaterial through the vacuum deposition of metal thereon from metalvapors, and is primarily directed to a method and apparatus for feedingstrip and sheet material through a coating apparatus.

At the present time, it is common in the art of vacuum metallizing tocoat with met-al from a vapor source onto =many exible substrates lbywhat is commonly referred to as a continuous batch process. In this typeof process, a coil of the subst-rate is placed on a pay-olf stand, thenit is threaded over .rolls carrying it over the vapor source or sources,`and finally onto a recoller roll, a-ll of the above equipment beingenclosed in a chamber designed to be capable of withstanding highinternal vacuum. The coating unit is then closed, evacuated to theproper vacuum of about 1 micron, and then the vapor sources areactivated while the substrate is carried over the vapor sources from thepay-off stand to the recoiler. After one coil is coated, the vacuum isbroken, air admitted, the coil of coated substrate is removed, and a newcoil of uncoated substrate is placed on the .pay-ott stand to start thebatch cycle again. This continuous batch process is not economic forlarge quantities because of the relatively great amount ofnon-productive ldown time required in the removing of the coil of coatedsubstrate, placing another coil of uncoated substrate on the pay-olistand, and then re-evacuating the coating unit to requisite very highvacuum.

Accord-ing to the instant invention, it is proposed to pr-ovide acomplete production line with the prod-uct of such a line -being acontinuously coated strip of a substrate material, such as steel, in anydesired width, for example, a 36 inch wide stri-p, and Kof any desiredguage within the general range `of 0.002 inch to 0.125 inch, with amet-allized coating, such as aluminum, having a thickness within thepotential ranges of vacuum metallized coatings, 0.000002 inch 'to0.00020 inch, and do so at commercially feasible speeds of 200 to 1,000feet per minute, giving a product with a bright, adherent and corrosionresistant aluminum coating.

Accordingly, it is an object of the invention to prOu vide acontinuously available supply of substrate for feeding through -a vacuumdepositing apparatus, the substr-ate being in the form of a continuousstrip which may be continuously fed through the coating apparatus at the`desired demand rate, thereby eliminating the periodic shut down of thecoating apparatus as is required with substrates of limited lengths inthe continuous batch method 'and equipment.

Another object of the invention is to provide in conjunction with anapparatus for cleaning metal substrate and applying a metal coatingthrough a vacuum met-al depositing process an Iapparatus for joiningcoils of thin metal stock in strip form into a continuous strip for thecontinuous feeding thereof through a cleaning and vacuum depositiongmetal coating apparatus at the demand rate of the cleaning and coatingapparatus, the coil joining apparatus including a looping tower forretaining an avail- -able supply of metal stock to be fed t-o thecleaning and coating lapparatus during the time interval required toplace a new coil `of metal stock into place and to join the `lead-ingend of the new coil to the trailing end of the prior coil, and a weldingmechanism for joining trailing and leading ends lof coils.

Still another object of the invention is to provide an :apparatus forjoining coils of metal stock into a continuous strip for feeding to anapparatus for metal coating the strip through a vacuum depositingprocess, the joining apparatus including means for supporting a coil ofmetal stock for unreel-ing, a shear aligned with the coil s-upport forcutting ott trailing and leading end portions of metal stock to assurethe matching of ends of coils to be joined, a joint Welder aligned withthe coil support and the shear for welding together matching ends ofcoils of :metal stock, and a weld grinder aligned .with the i jointWelder to grind the joint between adjacent coils to the thickness of themetal stock lof the coils to prevent interference with seals of thecoating apparatus receiving the metal stock.

A further object of the invention is to provide a continuously operatingproduction l-ine for the coating of sur- `faces of strip material inwhich the coating apparatus includes a plurality of metal vaporizers forthe vacuum rmetal'lization of the strip on opposite surfaces thereof,and a Ispare metal vaponizer for each active vaporizer whereby shut downof the production line due to the failure or necessity for replacementof a vaporizer is eliminated.

Yet another object o-f the invention is to provide in a continuouslyoperating production line for the metallizing of strips, -a coatingapparatus having separate vaporizers for coating opposite surfaces ofstrips, the total coating capacity lof vaporizers for one surface of -astrip being greater than the total capacity of vaporizers for the othervsurface of the strip wherein a differentially coated strip is formed.

A still further object of the invention is to provide a novel method ofcontinuously vacuum aluminum coating strip material wherein the stnipmaterial is provided in individual coi-ls, the leading and trailing endsof adjacent coils of strip material being welded together to form `acontinuous strip which is provided to a continuously operating coatingapparatus, at the demand rate thereof, after which the coated strips areagain wound in coils and sheared from the continuous strip, thecontinuous strip passing through a looping tower and being temporarilystored during the changing of coils between recoiling operations.

Still another object of the invention is to provide a novel apparatusand method for continuously vacuum metal coating metal strip materialwherein the strip material is provided in individual coils, the leadingand trailing ends of adjacent coils of strip material being weldedtogether to form a continuous strip which is supplied to Ia continuouslyoperating coating `apparatus at the operat- .ing rate thereof, afterwhich the coated strip material is cut into individual lsheets andpassed through a classifying -apparatus for detecting and removingsheets having pin hoi-e defects therein.

With these and other objects in view as will appear in the course of thefollowing description and claims, an illustrative embodiment is shown onthe accompanying drawings which show the successive steps inconventionalized form.

In the drawings:

FIGURES l and lA are schematic elevational views showing the generalarrangements of the components of the production line.

FIGURE 2 is an enlarged elevational view showing the details of one ofthe metal vaporizers.

FIGURE 3 is an enlarged sectional view showing the details of a typicalvacuum seal.

FIGURE 4 is a schematic elevational view of a modified tail end of theproduction line of FIGURES 1 and lA, and shows the details of a sheetcutter and a sheet classifier.

ln the drawing, a steel strip S is supplied in the form of coils C whichare individually mounted on a pay-olf stand to facilitate the unwindingof the strip S, the pay-off stand 5 having an arbor 6 receiving the coilC. After the strip S is unwound from the coil C, it f1rst passes througha shear, generally referred to by the numeral 7, which is aligned withthe pay-olf stand 5. The shear 7, in its simplest form, includes a fixedanvil 8 and a vertically movable blade 9 which cooperates with the anvilto cut off the trailing end of the strip S of one coil C and the leadingend of the strip S of another coil C in matching relation.

A joint Welder 10 is positioned adjacent `the shear 7 and receives thesheared trailing end and the shearcd leading end of a pair of strips S.The joint Welder 10 is preferably of an electric type and includes apair of electrodes 11, 12 disposed in opposed relation above and belowthe path of travel of the strips S.

A butt weld is formed between the trailing end of the one strip S andthe leading end of the second strip S, and in the formation thereofrough upset metal is disposed on opposite surfaces of the strips S whichare now welded into one. In order to provide smooth surfaces for passagethrough vacuum seals to be described in detail hereinafter, a grinder,generally referred to by the numeral 13, is provided. The grinder 13includes a pair of grinding wheels 14, 15 disposed in opposed relationto the opposite surfaces of the strip S. After the grinding operationhas been completed, the strip S is for all purposes one uninterruptedstrip.

It is the intention of the invention that the strip S be continuouslysupplied at the demand rate of the coating apparatus which will bedescribed in detail hereinafter. After a strip S has been completelyunwound from its coil C, it is necessary that movement of the trailingend of the strip S be discontinued until such time as another coil C maybe placed on the mandrel 6 of the pay-off stand 5,y and the weld betweenthe two strips S formed and ground. To make the continuous feed of thestrip S to the coating apparatus possible under these conditions, alooping tower, generally referred to by the numeral 16, is provided. Thelooping tower 16 includes a frame 17 on which a fixed in-feed roll 18and a fixed out-feed roll 19 are mounted in generally horizontalalignment. An upper roll support 20 is supported by the upper part ofthe frame 17, and a plurality of upper rolls 21 are conlnected to theupper roll support 20. A carriage 22 is mounted in a guideway 23 of theframe 17 for vertical movement and carries a lower roll support 24 formovement with the carriage 22 towards and away from the upper rollsupport 22. A plurality of lower rolls 25 are carried by the lower rollsupport 24; the lower rolls 25 being one less in number than the upperrolls 21 and stagi gered relative thereto. The strip S passes under theinfeed roll 1S, up and over one of the upper rolls 21, back and forthbetween and around the upper rolls 21 and the lower rolls 25, andfinally down from one of the upper rolls 21 and under the out-feed roll19.

The trailing end portion of a strip S is held against movement into thelooping tower 16 by a clamp unit, v

generally referred to by the numeral 26, mounted on the frame 17 inadvance of the looping tower 16. The clamp vunit 26 includes a fixedclamp member 27, which is ,the strip S therebetween when the liuid motor30 is actuated, thus preventing the pulling of the trailing end of thestrip S into the looping tower 16.

rl`he strip S, the surface of which is assumed to be only moderatelycleaned, passes from the out-feed roll 19 into a cleaning apparatuswhich includes a tank 32 which illustratively contains an aqueoussolution 33 of an alkali such as alkaline orthosilicate or alklinephosphte, with an inhibitor and a wetting agent, such as that preparedwith the product known in commerce by the trademark Orthosil. Adesirable concentration is 4 ounces per gallon at 170 to 190 F. Thestrip S preferably is subjected to electrolysis in the bath solution 33,e.g., as the cathode between a pair of spaced plates 34. The plates 34are connected by conductors 35 to a generator G.

From the tank 32, the strip S passes into a scrubbing unit. Thescrubbing unit includes a tank 36 in which rotating upper and lowerscrubbing brushes 37 are positioned above and below the strip S,respectively, for removing surface residues. Cold water jets 38 aredirected onto the strip S, both from above and below, in advance of andrearwardly of the scrubbing brushes 37.

From the scrubbing tank 36, the strip S may be passed into a tank 39containing an acid bath 40. This bath illustratively is a warm 4 percentaqueous solution of sulfuric acid, containing about 1/2 percent ofyellow phosphorus prepared in carbon disulfide solution and thoroughlymixed therein. The tank 39 has a pair of spaced plates 41 thereinbetween which the strip S passes. The plates 41 are connected byconductors 42 to a generator G, so that the steel strip is cathodic. Alow-voltage, low-amperage current of about 1/2 ampere per square inch ofstrip surface is employed. A desirable temperature of the electrolyte is150 F.

In practice, low carbon steel may have a content of 0.05 to 0.10 partper million of hydrogen. The cathodic charging of low carbon steel in anacid bath can store up to about 3 parts per million of hydrogen therein.When the yellow phosphorus is present in the acid bath, the cathodiccharging can effect storage of up to l4 parts per million. Theexpression of parts per million refers to parts by weight: that is, onepart per million means that 0.0001 percent by weight of hydrogen ispresent in the ferrous material. This hydrogen storage occurs within theatomic lattice structure of the ferrous body. The accepted value ofsolubility of hydrogen in the ferrous metal is less than 0.01 part permillion at room temperature. Cathodic treatment with the instant acidbath with phosphorus results in hydrogen, nascent form, being releasedat the surfaces of the strip S and the storing of the hydrogen withinthe strip.

The strip S next passes through a cold water rinse 43 and then through ahot water rinse 44. The strip S next passes through a hot air drier 45which includes a pair of hot air ducts 46 disposed above and below thestrip and directing hot air upon the surfaces of the strip to dry thesame.

After drying, the strip S moves into engagement with an in-feed driveunit, generally referred to by the numeral 47. The in-feed drive unitincludes a base 48 having an upstanding shaft 49 on which a frame 50 ismounted for limited rotation. A pair of driven wrap-around rolls 51 aresupported by the frame for movement therewith. The rotation of the frame50 is controlled by a gear drive 52 ,and a reduction gear unit 53 drivenby an electric motor 54. In this manner, alignment of the strip S may becontrolled by a pair of control devices 55 for the electric motor 54,which is of the reversible type, the control devices 55 being positionedadjacent the edges of the strip S and engaged thereby when the stripbecomes misaligned.

A vacuum chamber, generally referred to by the numeral 56, is disposednext to the in-feed drive unit 47. The vacuum chamber 56 includes ahousing 57 which has' a pair of end walls 58, and a pair of partitionwalls 59, dividing the housing into compartments 60, 61, and 62.

The compartment 60 is in the form of an antechamber and the entrancethereinto is sealed by a vacuum seal 63. The compartment 60 is evacuatedthrough a Vacuum pump line 64 which is connected to a conventional typeof vacuum pump (not shown), the pressure within the chamber 60 isreduced to from 1 to 20 mm. of mercury from the normal atmosphericpressure of 760 mm. of mercury.

A second vacuum seal 65 is disposed at the entrance to the compartment61 which is a heater compartment. A vacuum pump line 66 for a highcapacity booster pump is connected to the compartments 61 and 62, andthe pressure therein is reduced down to from 0.005 to 0.020 millimeterof mercury (5 to 20 microns). A third vacuum seal 67 is disposed at theentrance to the compartment 62. The vacuum seals 63, 65 and 67 may beidentical, and a typical one thereof will be described in detailhereinafter.

The strip S, in passing through the heater compartment 61, is heated,illustratively by induction coils 68 supplied with high frequencycurrent from conventional supplies. The strip S is thereby heated to 400to 1,200 degrees F., for example, wherewith the rate of hydrogenwithdrawal is increased manyfold. Although the solubility factor ofhydrogen in steel is also increased, it remains below one part permillion at 1,000 degrees F., as compared to 2 to 12 or more parts permillion, which may be stored in the ferrous base. The hydrogen thereforeis withdrawn at the surface of the strip S, and diffuses from theinterior of the strip body rapidly and in proportion as the surfacelayers are stripped of excess hydrogen. This hydrogen is released at thesurface of the strip largely in atomic or nascent form, and is highlyreactive as compared to the prior employments of super-atmosphericpressures of molecular hydrogen around the ferrous base. As the atomichydrogen passes any superficial surface oxide, it displaces the oxygentherefrom and Water vapor is formed and expelled from the strip surfaceby subsequent hydrogen atoms.

In practice, the pressure in the compartment 61 is held at to 50microns, with the vacuum pump line 64 removing Water vapor and hydrogen.Preferably, the rate of travel and the time of vacuum heating exposureis such that the stored hydrogen is reduced to a fraction of its initialvalue. The pressures specified for compartment 61 are more economicalthan maintenance of pressures of l micron or below which are requisitefor good vacuum metallizing of the cleaned strip.

After passing through the seal 67, the surface of the strip S has beencleaned sufficiently to obtain proper bonding of metal vapor to thestrip surface. Due to the heatting of the strip S Within the heatercompartment 61, the temperature of the strip S may be above thetemperature for restricting alloying of aluminum with the steel strip Sand it may be necessary to cool the strip S back to the temperature of200 to 600 degrees F. required to minimize alloying and obtain bondingdepending on the time factor and natural radiation heat losses. This maybe accomplished by either forming the seal 67 as a cooling seal, as isillustrated, or by providing separate cooling apparatus, such as by useof Water cooled rollers (not shown), within the compartment 62 forcooling the strip S.

Although it may be necessary to cool the trip S when coating withaluminum, it may be necessary to heat the strip S when other metals arebeing deposited on the strip S. For example, induction heating coils 69,supplied With high frequency current from a conventional supply 74), maybe required in the compartment 62 to bring the strip `S back to abonding temperature of 400 to 1,000 degrees F., depending on the timefactor and natural radiation heat losses, When the metal being depositedis titanium.

A metallizing chamber 71 is disposed next to the compartment 62 and isseparated therefrom by a slit seal 72. The pressure within themetallizing chamber 71 is maintained at no more than 1 micron through anevacuation connection '73 to a group of diffusion, booster and backuppumps, as known in the art. The pressure within the precedingcompartment 62 being approximately 20 microns, and under this lowpressure differential and at these low pressures where gas molecule freepaths are very long, a simple slit is adequate to separate thecompartment 62 from the chamber 71 and minimize gas How from one intothe other.

Within the metallizing chamber 71, the strip S passes around a pluralityof guide rolls 74 arranged to define a rectilinear generally S-shapedpath. As the strip S passes along a rst and upper horizontal run, itpasses between and is exposed to aluminum or other metal vapor from apair of opposed active vaporizers disposed above and below the strip Sand generally referred to by the numeral 75. Thus, vapor may bedeposited on both surfaces of the strip when they are within the desiredtemperature range. In addition to the active vaporizers 75, there arealternative vaporizers, generally referred to by the numeral 76, whichcan be made active when it becomes necessary to remove and renew thevaporizers 75. Thus conceptually, the line need not be stopped uponerosion, corrosion, or burn-out of any vaporizer.

After a thin coating of aluminum has been deposited on opposite surfacesof the strip S under optimum conditions, additional active vaporizers 75may be used in any desired number to build up the initially bonded thincoatings to the desired thickness. In the drawing, an additional activevaporizer 7S is shown coating the lower surface of the strip S, afterwhich the strip is reversed in travel direction and two additionalactive vaporizers 75 deposit aluminum or other metal vapor on what wasoriginally the upper strip surface. Each of the additional vaporizers 75will have a corresponding spare vaporizer 76. Not only may the totalnumber of vaporizers be varied to vary total thickness of aluminumcoating, but also the number of vaporizers coating one strip surface maybe greater than those coating the opposite strip surface, therebyobtaining What may be called a differentially coated strip. For example,one surface may have a coating of 0.000015 inch thickness and theopposite surface a coating of 0.000030 inch thickness.

A typical vaporizer 75, 76, as shown in FIGURE 2, includes a sleeve-likehousing 77 having a dispensing opening through which the aluminum vapormust flow to escape. Within the housing 77, a vaporizing element 78extends between a pair of bus bars 79, S0 and is resistively heated bycurrent from the bus bars. The coating metal can be supplied to theheated vaporizing element 78 in the form of a wire 81 which melts uponstriking the surface of the heated element 78 and the molten metalevaporated at the low pressure, so that its vapor deposits on the stripS.

' In order to facilitate the repair or replacement of components of thevaporizers 75, 76, the housing 77 may, for example, be rotatably mountedin sealed relation within a fixed second sleeve-like housing 77 whichhas a permanently upwardly directed dispensing opening. When theVaporizer 75, '76 is inactive, the dispensing openings of the housings77, 77 are out of alignment, and access to the interior of the housing77 may be had through one end thereof Without affecting the pressureWithin the metallizing chamber 71. The housings 77, 77' will, of course,be provided with suitable ends to prevent leakage of air into themetallizing chamber 71 when the dispensing openings of the housings 77,77' are aligned.

Although the drawing shows the vaporizers in horizontal planes and thestrip S moving in horizontal planes during the coating operation, thisis not intended to be restrictive. The strip may travel in a verticaldirection with slanted vaporizers on both sides of the strip coating andsimultaneously coating both surfaces thereof. Here again, the number ofvaporizers for the different strip surfaces being coated may be variedto obtain a differentially coated strip. A differentially coated stripmay also be obtained by means other than varying the number ofVaporizers. For example, smaller vaporizers may be provided for onesurface of the strip, or the vaporizers for one surface may be operatedat a lower evaporative rate. However, the use of different numbers ofvaporizers will normally provide the greatest operating flexibility.

When leaving the metallizing chamber 71, the strip S pasess through asecond slot seal 82 into a chamber 83 wherein the pressure is maintainedat approximately microns by an evacuation connection S4. Water cooledplates 85 are mounted within the chamber 33 adjacent the surfaces of thestrip S for cooling the same.

The strip S next enters a chamber 86 through a seal S7. The seal 87 maybe of the same type as the seals 63, 65 and 67, although it may bedesirable to water cool the housing thereof. The pressure within thechamber 86 is maintained in the vicinity of l to 20 mm. of mercurythrough an evacuation connection 88. The strip S then passes to theatmosphere through a seal 89 which is identical to the seals 63, 65 and67.

After leaving the seal 89, the strip S passes to a tension stand 90. Thetension stand 90 includes a pair of driven wrap-around rolls 91 aboutwhich the strip S passes. The wrap-around rolls 91 are driven at a speedin proportion to the speed of the wrap-around rolls 51 to maintain thedesired constant tension in the strip, and thereby assure optimumtracking, eliminating sidewise weaving other than that weave unavoidablefrom the camber in commercially rolled strips.

The strip S then enters a looping tower 92 which may be identical withthe looping tower 16. However, while the looping tower 16 is normallyloaded to provide a strip supply while another coil C is being joined tothe strip S, the looping tower 92 is normally empty and available forthe temporary storage of a quantity of the coated strip S.

A speed-up strip drive stand 93 is disposed adjacent the looping tower92 and includes a pair of wrap-around rolls 94 about which the coatedstrip S passes. A shear 95, similar to shear 7, is disposed next to thespeed-up strip drive stand for cutting the coated strip into individualcoils C'. The coils C are wound on a mandrel 96 of a multiple mandrelcoil winding stand 97,`which is the terminal component of the productionline. The speed-up strip drive stand 93 drives the coated strip S at aspeed faster than the line speed, thus emptying the looping stand 92during the winding of a coil C' of the coated strip S and rendering thelooping stand 92 available for storage of additional strip during thechanging of coils C'.

A typical seal, which for purposes of identication will be considered tobe the seal 63, is 3. The seal 63 includes a housing 98 having a strippassage 99 extending longitudinally therethrough. Opposed pairs ofpockets 100 are formed in the housing 99 on opposite sides of the strippassage 99 and opening thereinto. A roller bearing block 101 is disposedin each of the cavities 100 and supports a roller 162. The rollers 102engage opposite surfaces of the strip S passing therebetween and forni aseal therewith, one roller of each pair of rollers 102, together withits associated block 101, being resiliently urged towards the strippassage 99 and the strip S disposed therein by a spring 103.

The vacuum seals 63, as well as other equivalent Seal structures, wouldbe scarred or marred and their sealing efficiency diminished if the weldjoint were not ground, as previously set forth hereinabove, or otherwisesmoothed and reduced to a thickness not much exceeding the thickness ofthe normal strip S. Also, at this time, it is again pointed out that itis essential to shear in carefully aligned relationship the stripportions to be joined together in order that the continuous strip S bestraight throughout to assure tracking of the strip S through the vacuumchamber, and thereby avoid sidewise motion which would otherwise jam theentire operation.

Reference is now made to FIGURE 4, wherein the deiuustrared in FIGUREtails of a modified tail end of the production line of FIG- URES 1 and1A are illustrated. In this form of production line, the coated strip Spasses from the tension stand 90 to a sheet cutter, generally referredto by the numeral 110. The sheet cutter is illustratively shown asincluding a pair of rolls 111, 112 having mating offset portions foreffecting the desired shearing action. The diameters of the rolls 111,112 may be varied to vary the lengths of the sheets cut from thecontinuous strip S. The sheets are referred to by the numeral 113.

After the sheets 113 are formed by the action of the sheet cutter 11d,the sheets move along a suitable guide 114 to a sheet classifier,generally referred to by the numeral 115. Any suitable type ofconveyance means may be provided for so moving the sheets. The sheetclassiiier 115 is utilized to detect pin holes which may exist in thesheets 113 and to remove defective sheets.

The sheet classifier basically includes a bright light source 116 on oneside of the path of the sheets 113, and photoelectric cell units 117 onthe other side of the path. When a sheet 113 moves between the lightsource 116 and the photoelectric cell units 117 and there is a pin holein the sheet, light through the pin hole activates a photomultipliertube of one of the photoelectric cell units 117. Illustratively, theguide 114 includes a movable section 118 which may be tilted to reject adefective sheet 113. The guide section 118 may be positioned by anelectrically operated device 119 which is connected to the photoelectriccell units 117 and the operation of the device 119 controlled thereby.The circuit for the device 119 may include spaced switches 120 which areboth closed only when the sheet 113 to be inspected is aligned with thelight source 116 and the photoelectric cell units 117, therebypreventing the operation of the device 119 due to the spacing betweenadjacent ones of the sheets 113.

With a fast moving line, when the device 119 is actuated, as many as veor six sheets 113 will be directed from the line by the movement of theguide section 118. Accordingly, a manual inspection of the discardedsheets 113 may be required to separate the defective one.

The foregoing has been specically directed to the application ofaluminum coatings on steel substrates. However, the invention is notintended to be so limited. In addition to aluminum, the fourth periodtransition metals (Ti, V, Cr, Mn, Fe, Co, Ni) may be employed as thecoating metals. The coatings on the opposite side of the substrate neednot be of the same metal, but may be of two different metals of theaforementioned metals, and the two different metal coatings may be ofdifferent thicknesses. For example, a metal coated metal strip ofparticular potential utility to can makers would be a ferrous substratehaving an easily solderable metal on the surface which would be theoutside of a can and a protective metal on the surface which would bethe inside of the can. A thin coating of cadmium on the outside wouldgive easy solderability and excellent resistance to rusting whereastitanium may be used on the inside for corrosion resistance to foods.Also, the complete process may be employed in conjunction with metalsubstrates, other than ferrous substrates, which are capable of hydrogenabsorption.

Further, other substrates that do not absorb hydrogen may be coated withmetals in accordance with the disclosed process by eliminating the stepof charging the substrate with hydrogen in the cleaning operation priorto the vacuum metallizing operation.

In considering the use of the described apparatus for the application ofcoatings of diiferent metals, it is pointed out that the temperature ofthe substrate at the time the metal vapor of the coating metal strikesthe substrate will vary depending upon the coating metal. In someinstances, it will be necessary to cool the strip S as it enters thechamber, and in other instances, it will be necessary to heat the stripS. When coating a steel substrate with aluminum, the temperature of thestrip S should be between 300 degrees and 500 degrees F. when thealuminum vapor hits it. When this temperature range is maintained, theresulting coating is less porous, somewhat coarser in grain size andnoticeably more resist-ant to corrosion than if the steel strip is cold,i.e., below 150 degrees F. On the other hand, if the steel strip is toohot, e.g., 700 degrecs to 900 degrees F., some detectible brittle alloy,Fe2Al5, is formed at the iron-aluminum interface and this is detrimentalto fabrication of the coated strip. On the other hand, when coating withtitanium and chromium, it has been found necessary to have the steelstrip at temperatures of 700 degrees to 900 degrees F. at the time themetal vapor hits the strip if an adherent coating is to be obtained.

The illustrative embodiments are not restrictive, and the invention maybe practiced in many Ways Within the scope of the appended claims.

We claim:

1. A method of continuous metal coating a metal strip comprising thesteps of providing the strip material in individual coils, transverselyshearing the trailing end of a lirst coil and the leading end of asecond coil at substantially the same angle to assure the mating of theends of the coils, welding together the strip material of the individualcoils in end-to-end relation to form a continuous strip, finishing thesurfaces of the continuous strip in the Weld area to form a joint havingsmooth sealable surfaces and a thickness substantially less than thecombined thickness of the two joined strip material, storing certain ofthe continuous strip to assure a continuous supply of strip materialduring the time required for the addition of another coil of stripmaterial to the continuous strip, passing the strip through anelectrolytic apparatus to clean and charge the strip with hydrogen,rinsing the strip, drying the strip, passing the strip through a sealinto a vacuum chamber and maintaining a tension on the strip WhileWithin the vacuum chamber to facilitate tracking along a predeterminedpath Within the vacuum chamber, heating the strip to remove gases andoxides from the strip, thermally treating the strip to maintain thestrip at the desired coating temperature, depositing metal on oppositesurfaces of the strip from sources of metal vapor by condensation ofmetal vapor on the moving strip, passing the strip out of the vacuumchamber through a seal, rewinding the coated strip material in coilform, together with the storing of portions of the coated strip materialas it passes out of the vacuum chamber during the removal of a coil andfeeding the coated strip material during the Winding of a coil at afaster rate than the feed rate through the vacuum chamber tosubstantially deplete the stored coated strip material, and then cuttingot the individual coil.

2. `A method of continuous metal coating a metal strip comprising thesteps of providing the strip material in individual coils, transverselyshearing the trailing end of a rst coil and the leading end of a secondcoil at substantially the same angle to assure the mating of the ends ofthe coils, welding together the strip material of the individual coilsin end-to-end relation to form a continuous strip, finishing thesurfaces of the continuous strip in the Weld area to form a joint havingsmooth sealable surfaces and a thickness substantially less than thecombined thickness of the two joined strip material, storing certain ofthe continuous strip to assure a continuous supply of strip materialduring the time required for the -addition of another coil of stripmaterial to the continuous strip, passing the strip through anelectrolytic apparatus to clean and charge the strip with hydrogen,rinsing the strip, drying the strip, passing the strip through a sealinto a vacuum chamber 4and maintaining a tension on the strip Whilewithin the vacuum chamber to facilitate tracking along a predeterminedpath Within the vacuum chamber, heating the strip to remove gases andoxides from the strip, thermally treating the strip to maintain thestrip at the desired coating temperature, depositing different metals1t) on opposite surfaces of the strip from sources of metal vapor bycondensation of metal vapor on the moving strip, passing the strip outof the Vacuum chamber through a seal, rewinding the coated stripmaterial in coil form, together with the storing of portions of thecoated strip material as it passes out of the vacuum chamber during theremoval of a coil and feeding the coated strip material during theWinding of a coil at a faster rate than the feed rate through the vacuumchamber to substantially deplete the stored coated strip material, andthen cutting olf the individual coil.

'3. A method of continuous metal coating a metal strip comprising thesteps of providing the strip material in individual coils, transverselyshearing the trailing end of a rst coil and the leading end of a secondcoil at substantially the same angle to assure the mating of the ends ofthe coils, Welding together the strip material of the individual coilsin end-to-end relation to form a continu- Ious strip, finishing thesurfaces of the continuous strip in the Weld area to form a joint havingsmooth sealable surfaces and a thickness substantially less than thecombined thickness of the tWo joined strip material, storing certain ofthe continuous strip to assure a continuous supply of strip materialduring the time required for the addition of another coil of stripmaterial to the continuous strip, passing the strip through anelectrolytic apparatus -to clean and charge the strip with hydrogen,rinsing the strip, drying the strip, passing the strip through a sealinto a vacuum chamber and maintaining a tension on the strip whilewithin the vacuum chamber to facilitate tracking along a predeterminedpath within the vacuum chamber, heating the strip to remove gases andoxides from the strip, thermally ltreating the strip to maintain thestrip at the desired coating temperature, depositing metal coatings ofdifferent thickness on opposite surfaces of the strip from sources ofmetal vapor by condensation of metal vapor on the moving strip, passingthe strip out of the vacuum chamber through a seal, rewinding the coatedstripmaterial in coil form, together with the storing 0f portions of thecoated strip material as it passes out of the vacuum chamber during theremoval of a coil and Ifeeding the coated strip 'material during theWinding of a coil at a faster rate than Ithe feed rate through thevacuum chamber to substantially deplete the stored coated stripmaterial, and then cutting otf the individual coil.

4. A method of continuous aluminum coating a steel strip comprising thesteps of providing the strip material in individual coils, transverselyshearing the trailing end of a first coil and the leading end of asecond coil at substantially the same angle to assure the mating of theends of -the coils, welding together the strip material of theindividual coils in end-to-end relation to form a continuous strip,tinishing the surfaces of the continuous strip in the Weld area to forma joint having smooth sealable surfaces and a thickness substantiallyless than the combined thickness of the two joined strip material,storing cer-tain of the continuous strip to assure a continuous supply-of strip material during the time required for the addition of anotherooil of strip material to the continuous stril passing the strip throughan electrolytic app-aratus to clean and charge the strip with hydrogen,rinsing the strip, drying the strip, passing the strip through a sealinto a vacuum chamber and maintaining a tension 'on the strip whilewithin the vacuum chamber to facilitate tracking along a predeterminedpath within the vacuum chamber, heating the strip to remove gases andoxides -from the strip, thermally treating the strip to maintain thestrip at the desired coating temperature, depositing aluminum on onesurface of the steel strip from a source of metal vapor by condensationof aluminum vapor on the moving strip, passing the strip out of thevacuum ychamber through a seal, rewinding the coated strip material incoil form, -together with the storing of portions of the coated stripmaterial as it passes out of the vacuum chamber during the removal of acoil and feeding the coated strip material during the winding of a coilat a faster rate than the feed rate through the vacuum chamber tosubstantially deplete the stored coated strip material, and then cuttingoff the individual coil.

5. A method of continuous metal coating a metal strip comprising thesteps .of providing the strip material in individual coils, transverselyshearing the trailing end of a first coil and the leading end of asecond coil at substantially the same angle to assure the mating of theends of the coils, connecting together the strip material of theindividual coils in end-to-end relation to form a continuous strip witha joint having smooth sealable surfaces and a thickness substantiallyless than the combined thickness of the two joined strip material,storing certain of the continuous strip to assure a continuous supply ofstrip material during the time required for the addition of another coilof strip material to the continuous strip, passing the strip through anelectrolytic apparatus to clean and charge the strip with hydrogen,rinsing the strip, drying the strip, passing the strip through a sealinto a vacuum chamber and maintaining a tension of the strip whilewithin the vacuum chamber to facilitate tracking along a predeterminedpath within the vacuum chamber, heating the strip to remove gases andoxides from the strip, thermally treating the strip to maintain thestrip at the -desired coating temperature, depositing metal on oppositesurfaces of the strip from sources of metal vapor 1y condensation ofmetal vapor on the moving strip, passing the strip out of the vacuumchamber through a seal, rewinding the coated strip material in coil formtogether with the storing of portions of the coated strip material as itpasses out of the vacuum chamber during the removal of a coil andfeeding the coated strip material during the winding of a coil at afaster rate than the feed rate through the vacuum chamber tosubstantially deplete the stored coated strip material, and then cuttingoff the individual coil.

6. A method of continuous metal coating a metal strip comprising thesteps of providing a continuous metal strip, passing the strip throughan electrolytic apparatus to clean and charge the strip with hydrogen,rinsing the strip, drying the strip, passing the strip through a sealinto a vacuum chamber and maintaing a tension on the strip while `withinthe vacuum chamber to facilitate tracking along a predetermined pathwithin the vacuum chamber, heating the strip to remove gases and oxidesfrom the strip, thermally treating the strip to maintain the strip atthe desired coating temperature, depositing metal on opposite surfacesof the strip from sources of metal vapor by condensation of metal vaporon the moving strip, passing the strip out of the vacuum chamber througha seal, and cutting the coated strip into readily handleable units.

7. A method of continuous metal coating a meal strip comprising thesteps of providing a continuous strip, passing the strip through anelectrolytic apparatus to clean and charge the strip with hydrogen,rinsing the strip, drying the strip, passing the strip through a sealinto a vacuum chamber and maintaining a tension on the strip Whilewithin the vacuum chamber to facilitate tracking along a predeterminedpath Within the vacuum chamber, heating the strip to remove gases andoxides from the strip, thermally treating the strip to maintain thestrip at the desired coating temperature, depositing metal on oupositesurfaces of the strip from sources of metal vapor by condensation ofmetal vapor on the moving strip, passing the strip out of the vacuumchamber through a seal, rewinding the coated strip material in coilform, together with the storing of portions of the coated strip materialas it passes out of the vacuum chamber during the removal of a coil andfeeding the coated strip material during the winding of a coil at afaster rate than the feed rate through the vacuum chamber tosubstantially deplete the stored coated strip material, and then cuttingoff the individual coil.

8. A method of continuous metal coating a metal strip comprising thesteps of providing the strip material in individual coils, transverselyshearing the trailing end of a first coil and the leading end of asecond coil at substantially the same angle to assure the mating of theends of the coils, welding together the strip material of the individualcoils in end-to-end relation to form a continuous strip, finishing thesurfaces of the continuous strip in the weld area to form a joint havingsmooth sealable surfaces and a thickness substantially less than thecombined thickness of the two joined strip material, storing certain ofthe continuous strip to assure a continuous supply of strip materialduring the time required for the addition of another coil of stripmaterial to the continuous strip, passing the strip through anelectrolytic apparatus to clean and charge the strip with hydrogen,rinsing the strip, drying the strip, passing the strip through a sealinto a vacuum chamber and maintaining a tension on the strip whileWithin the vacuum chamber to facilitate tracking along a predeterminedpath Within the vacuum chamber, heating the strip to remove gases andoxides from the strip, thermally treating the strip to maintain thestrip at the desired coating temperature, depositing metal on oppositesurfaces of the strip from sources of metal vapor by condensation ofmetal vapor on the moving strip, passing the strip out of the vacuumchamber through a seal, and cutting the coated strip into a plurality ofsheets as the coated strip continuously moves.

9. A method of continuous metal coating a metal strip comprising thesteps of providing the strip material in individual coils, transverselyshearing the trailing end of a first coil and the leading end of asecond coil at substantially the same angle to assure the mating of theends of the coils, welding together the strip material of the individualcoils in end-toend relation to form a continuous strip, finishing thesurfaces of the continuous strip in the Weld area to form a joint havingsmooth scalable surfaces and a thickness substantially less than thecombined thickness of the two joined strip material, storing certain ofthe continuous strip to assure a continuous supply of strip materialduring the time required for the addition of another coil of stripmaterial to the continuous strip, passing the strip through anelectrolytic apparatus to clean and charge the strip with hydrogen,rinsing the strip, drying the strip, passing the strip through a sealinto a vacuum chamber and maintaining a tension on the strip WhileWithin the vacuum chamber to facilitate tracking along a predeterminedpath within the vacuum chamber, heating the strip to remove gases andoxides from the strip, thermally treating the strip to maintain thestrip at the desired coating temperature, depositing metal on oppositesurfaces of the strip from sources of metal vapor by condensation ofmetal vapor on the moving strip, passing the strip out of the vacuumchamber through a seal, cutting off the coated strip into a plurality ofsheets as the coated strip continuously moves, and passing the sheetsthrough a classifying apparatus to remove defective ones of the sheets.

10. A method of continuous metal coating a metal strip comprising thesteps of providing a continuous metal strip, passing the strip throughan electrolytic apparatus to clean and charge the strip with hydrogen,drying the strip, passing the strip through a seal into a vacuum chamberand maintaining a tension on the strip while within the vaccum chamberto facilitate tracking along a predetermined path within the vacuumchamber, heating the strip to remove gases and oxides from the strip,depositing metal on the strip from a source of metal vapor bycondensation of metal vapor on the moving strip, passing the strip outof the vacuum chamber through a seal, and cutting the coated strip intoa plurality of sheets as the coated strip continuously moves.

11. A method of continuous metal coating a metal strip comprising thesteps of providing the strip material in individual coils, transverselyshearing the trailing end of a first coil and the leading end of asecond coil at substani3 ti'ally the same angle to assure the mating ofthe ends of the coils, connecting together the strip material of theindivdual coils in end-to-end relation to form a continuous strip with ajoint having smooth sealable surfaces and a thickness substantially lessthan the combined thickness of lthe two joined strip material, storingcertain of the continuous strip to assure a continuous supply of stripmaterial during the time required for the addition of another coil ofstrip material to the continuous strip, passing the strip through anelectrolytic apparatus to clean and charge the strip with hydrogen,rinsing the strip, drying the strip, passing the strip through a sealinto a vacuum chamber and maintaining a tension on the strip whilewithin the vacuum chamber to facilitate tracking along a predeterminedpath within the vacuum chamber, heating .the strip to remove gases andoxides from the strip, thermally treating the strip to maintain thestrip at the desired coating temperature, depositing metal on oppositesurfaces of the strip from sources of metal vapor by condensation ofmetal vapor on the moving strip, passing the strip out of the vacuumchamber through a seal, and cutting the coated strip into a plurality ofsheets as the coated strip continuously moves.

12. A method of continuous aluminum coating a steel strip comprising thesteps of providing the strip material in individual coils, transverselyshearing the trailing end of a lirst coil and the leading end of asecond coil at substantially the same angle to assure the mating of theends of the coils, welding together the strip material of the individualcoils in end-to-end relation to form a continuous strip, finishing thesurfaces of the continuous `strip in the weld area to form a jointhaving smooth sealable surfaces and a thickness substantially less thanthe combined thickness of the two joined strip material, storing certainof the continuous strip to assure a continuous supply of strip materialduring the time required for the :addition of another coil of stripmaterial to the continuous strip, passing the strip through anelectrolytic apparatus to clean and charge the strip with hydrogen,rinsing the strip, drying the strip, passing the strip through a sealinto a vacuum chamber and maintaining a tension on the strip whilewithin the vacuum chamber to facilitate tracking along a predeterminedpath within the vacuum chamber, heating the strip to remove gases andoxides from the strip, thermally treating the strip to maintain thestrip at the desired coating temperature, depositing aluminum onopposite surfaces of the steel strip from -sources of metal vapor bycondensation of aluminum vapor on the moving strip, passing the stripout of the vacuum chamber through a seal, rewinding the coated stripmaterial in coil form, together with the storing of portions of thecoated strip material as it passes out of `the vacuum chamber during theremoval of a coil and feeding the coated strip material during thewinding of a coil at a faster rate than the feed rate through the vacuumchamber to substantially deplete the stored coated strip material, andthen cutting olf the individual coil.

13. A method of continuous aluminum coating a steel strip comprising thesteps of providing the strip material in individual coils, transverselyshearing the trailing end of a first coil and the leading end of asecond coil at substantially the same angle to assure the mating of theends of the coils, welding together the strip material of the individualcoils in end-to-end relation to form a continuous strip finishing thesurfaces of the continuous strip in the weld area'to form a joint havingsmooth sealable surfaces and a thickness substantially less than thecombined thickness of the two joined strip material, storing certain ofthe continuous strip to assure a continuous supply of strip materialduring the time required for the addition of another coil of stripmaterial to the continuous strip, passing the strip through anelectrolytic apparatus to clean and charge the strip with hydrogen,rinsing the strip, drying the strip, passing the strip through a sealinto a vacuum chamber and maintaining a tension on the strip whilewithin the vacuum chamber to facilitate tracking along a predeterminedpath within the vacuum chamber, heating the strip to remove gases andoxides from the strip, thermally treating the strip to maintain thestrip at the desired coating temperature, depositing aluminum indifferent thickness on opposite surfaces of the steel strip fromdiierent sources of metal vapor by condensation of aluminum vapor on themoving strip, passing the strip out of the vacuum chamber through aseal, rewinding the coated strip material in coil form, together withthe storing of portions of the coated strip -material as it passes outof the vacuum chamber during the removal of a coil and feeding thecoated strip material during the winding of a coil at afaster rate thanthe feed rate through the vacuum chamber to substantially deplete thestored coated strip material, and then cutting olf the individual coil.

14. An apparatus for the vacuum metal coating of metal strip materialcomprising a coil pay-oit stand, shear means for cutting off thetrailing end of a first strip portion and the leading end of a secondstrip portion in transverse matching relation, welding means adjacentsaid shear means for joining together the strip portions in alignedrelation to form portions of a continuous strip, means for finishing thewelded joint to provide smooth scalable surfaces and assuring a joint ofa thickness substantially less than the combined thickness of the twojoined strip portions, strip clamping means for holding the trailingportion of the continuous strip during the joining of a coil of stripmaterial thereto, a looping tower for receiving and storing intermediateportions of the strip to provide a continuous strip supply during theaddition of another strip portion to the strip, means for theelectrolytic cleaning of the metal strip and the charging of the stripwith hydrogen, rinsing means for rinsing the strip subsequent to theelectrolytic cleaning, a drier for removing moisture from the strip, acompartmented vacuum chamber, entrance and exit seals at the oppositeends of said vacuum chamber, tension means at opposite ends of saidvacuumhchamber and outside of said seals for maintaining v.theimoveinentof the continuous strip along a predeterminedpathwithin said vacuumchamber, strip heating `meansA ,vitllinone of said vacuum chambercompartments to remove gases and oxides from the strip, thermal controlmeans within said vacuum chamber for controlling the temperature of thestrip subsequent to the passage thereof past said strip heating means, aplurality of metal vaporizers within another of said vacuum chambercompartments on opposite sides of the path of the strip for vaporizingmetal and applying metal coating to opposite surfaces of the movingstrip through the condensation of the metal vapor on the strip, saidmetal vaporizers including active vaporizers and spare vaporizersdisposed in alternating relation whereby the replacement of metalvaporizers may be made during the continuous coating of the strip, saidexit seal having cooling means to preserve the components of said sealand to control the exit temperature of the strip, and means for cuttingoff the coated strip into readily handleable units.

15. The apparatus of claim 14 wherein the metal vaporizers effective incoating one surface of the strip have a greater output than the metalvaporizers effective in coating the other surface of the strip toprovide a differentially coated strip.

16. The apparatus of claim 14 wherein the strip cutoff means includesmeans for coiling the coated strip into coils, a second looping towerintermediate said tension means and said strip coiling means for storingintermediate portions of the coated strip during the removal of a coil,clamp means for holding an end of the coated strip during the removal ofa coil, feed means for feeding the coated strip to said strip coilingmeans at a rate faster than the feed rate of the strip through saidvacuum chamber to substantially exhaust the stored supply of coatedstrip within said second looping tower during each coil windingoperation, and means for cutting the coils from the strip.

17. The apparatus of claim 16 wherein the metal vaporizers effective incoating one surface of the strip have a greater output than the metalvaporizers effective in coating the other surface of the strip toprovide a differentially coated strip.

18. The apparatus of claim 14 wherein the strip cut-off means is in theform of sheet cutting means for cutting the strip into a plurality ofidentical sheets.

19. The apparatus of claim 18 wherein the metal vaporizers effective incoating one surface of the strip have a greater output than the metalvaporizers effective in coating the other surface of the strip toprovide a differentially coated strip.

20. The apparatus of claim 1S together with a sheet classifier havingmeans for detecting sheets having pin holes therein and removing suchsheets.

21. An apparatus for the vacuum metal coating of metal strip materialcomprising a coil pay-off stand, shear means for cutting otf thetrailing end of a rst strip portion and the leading end of a secondstrip portion in transverse matching relation, welding means adjacentsaid shear means for joining together the strip portions in alignedrelation to form portions of a continuous strip, means for finishing thewelded joint to provide smooth scalable surfaces and assuring a joint ofa thickness substantially less than the combined thickness of the twojoined strip portions, strip clamping means for holding the trailingportion of the continuous strip during the joining of a coil of stripmaterial thereto, a looping tower for receiving and storing intermediateportions of the strip to provide a continuous strip supply during theaddition of another strip portion to the strip, means for theelectrolytic cleaning of the metal strip, a compartmented Vacuumchamber, entrance and exit seals at the opposite ends of said vacuumchamber, tension means at opposite ends of said vacuum chamber andoutside of said seals for maintaining the movement of the continuousstrip along a predetermined path within said vacuum chamber, stripheating means within one of said vacuum chamber compartments to removegases and oxides from the strip, thermal control means within saidvacuum chamber for controlling the temperature of the strip subsequentto the passage thereof past said strip heating means, a plurality ofmetal vaporizers within another of said vacuum chamber compartments onopposite sides of the path of the strip for vaporizing metal andapplying metal coating to opposite surfaces of the moving strip throughthe condensation of the metal vapor on the strip, said metal vaporizersincluding active vaporizers and spare vaporizers disposed in alternatingrelation whereby the replacement of metal vaporizers may be made duringthe continuous coating of the strip, said exit seal having cooling meansto preserve the components of said seal and to control the exittemperature of `the strip, means for coiling the coated strip intocoils, a second looping tower intermediate said tension means and stripcoiling means for storing intermediate portions of the coated stripduring the removal of a coil, clamp means for holding an end of thecoated strip during the removal of a coil, feed means for feeding thecoated strip to said strip coiling means at a rate faster than the feedrate of the strip through said vacuum chamber to substantially exhaustthe stored supply of coated strip Within said second looping towerduring each coil winding operation, and means for cutting the coils fromthe strip.

22. An apparatus for the continuous vacuum metal coating of metal stripmaterial comprising means for supplying strip material in coils andjoining together the individual coils with joints having scalablesurfaces of and generally of the orginal thickness of the stripmaterial, a looping tower for receiving and storing intermediateportions of the strip to provide a continuous strip supply during theaddition of another strip portion to the strip, means for theelectrolytic cleaning of the metal strip and the charging of the stripwith hydrogen, rinsing means for rinsing the strip subsequent to theelectrolytic cleaning, a drier for removing moisture from the strip, acompartmented vacuum chamber, entrance and exit seals at the oppositeends of said vacuum chamber, tension means at opposite ends of saidvacuum chamber and outside of said seals for maintaining the movement ofthe continuous strip along a predetermined path within said vacuumchamber, strip heating means within one of said vacuum chambercompartments to remove gases and oxides from the strip, thermal controlmeans within said vacuum chamber for controlling the temperature of thestrip subsequent to the passage thereof past said strip heating means, aplurality of metal vaporizers within another of said vacuum chambercompartments on opposite sides of the path of the strip for vaporizingmetai and applying metal coating to opposite surfaces of the movingstrip through the condensation of the metal vapor on thestrip, means forcoiling the coated strip into coils, a second looping tower intermediatesaid tension means and said strip coiling means for storing intermediateportions of the coated strip during the removal of a coil, feed meansfor feeding the coated strip to said strip coiling means at a ratefaster than the feed rate of the strip through said vacuum chamber tosubstantially exhaust the stored supply of coated strip within saidsecond looping tower during each coil winding operation, and means forcutting the coils from the strip.

23. An apparatus `for the vacuum metal coating of metal strip materialcomprising a coil pay-off stand, shear means for cutting olf thetrailing end of a first strip portion and the leading end of a secondstrip portion in transverse matching relation, welding means adjacentsaid shear means for joining together the strip portions in alignedrelation to form portions of a continuous strip, means for finishing thewelded joint to provide smooth scalable surfaces and assuring a joint ofthickness substantially less than the combined thickness of the twojoined strip portions, strip clamping means for holding the trailingportion of the continuous strip during the joining of a coil of stripmaterial thereto, a looping tower for receiv ing and storingintermediate portions of the strip to provide a continuous strip supplyduring the addition of another Istrip portion to the strip, means forthe electrolytic cleaning of the metal strip, a compartmented vacuumchamber, entrance and exit seals at the opposite ends of said vacuumchamber, tension means at opposite ends of said vacuum chamber andoutside of said seals for maintaining the movement of the continuousstrip along a predetermined path within said vacuum chamber, stripheating means within one of said vacuum chamber compartments to removegases and oxides from the strip, thermal control means within saidvacuum chamber for controlling the temperature of the strip subsequentto the passage thereof past said strip heating means, a plurality ofmetal vaporizers within another of said vacuum chamber compartments onopposite sides of the path of the strip for vaporizing metal andapplying metal coating to opposite surfaces of the moving strip throughthe condensation of the metal vapor on the strip, said etal vaporizersincluding active vaporizers and spare vaporizers disposed in alternatingrelation whereby the replacement of metal vaporizers may be made duringthe continuous coating of the sheet, said exit seal having cooling meansto preserve the components of said seal and to control the exittemperature of the strip, and sheet cutting means for cutting the coatedstrip into a plurality of identical sheets.

24. An apparatus for the continuous vacuum metal coating of metal stripmaterial comprising means for Supplying Strip material in coils andjoining together the individual coils with joints having sealablesurfaces of and generally of the original thickness of the stripmaterial, a looping tower for receiving and storing intermediateportions of the strip to =provide a continuous strip supply during theaddition of another strip portion to the strip, means for theelectrolytic cleaning of the metal strip and the charging of the stripwith hydrogen, rinsing means for rinsing the strip subsequent to theelectrolytic cleaning, a drier for removing moisture from the strip, acompartmented vacuum chamber, entrance and exit seals at lthe oppositeends of said vacuum chamber, tension means at opposite ends of saidvacuum chamber and outsideV of said seals for maintaining the movementof the continuous strip along a predetermined path Within said vacuumchamber, strip heating means Within one of said vacuum chambercompartments to remove gases and oxides from the strip, thermal controlmeans Within said vacuum chamber for controlling the temperature of thestrip subesquent to the passage thereof past said strip heating means, aplurality of metal vaporizers Within another of said vacuum chambercompartments on opposite sides of the path of the strip for Vaporizingmetal and applying metal coating to opposite surfaces of the movingstrip through the condensation of the metal vapor on the strip, andsheet cutting means for cutting the coated strip into a plurality ofidentical sheets.

References Cited bythe Examiner UNITED STATES PATENTS 2,214,618 8/ 37Kenyon 29-33 2,311,139 2/43 Tainton 117-50 2,382,432 8/45 McManus et al.117-107 2,748,734 6/56 Kennedy 113-33 2,754,222 7/56 Healy et al. 117-532,812,270 11/57 Alexander 117-50 2,876,132 3/59 Worden et al. 117-502,887,984 5/59 Drummond 118-72 X 2,959,494 11/ 60 Shepard 117-107RICHARD D. NEVIUS, Primary Examiner.

1. A METHOD OF CONTINUOUS METAL COATING A METAL STRIP COMPRISING THESTEPS OF PROVIDING THE STRIP MATERIAL IN INDIVIDUAL COILS, TRANSVERSELYSHEARING THE TRAILING END OF A FIRST COIL AND THE LEADING END OF ASECOND COIL AT SUBSTANTIALLY THE SAME ANGLE TO ASSURE THE MATING OF THEENDS OF THE COILS, WELDING TOGETHER THE STRIP MATERIAL OF THE INDIVIDUALCOILS IN END-TO-END RLATION TOFORM A CONTINUOUS STRIP, FINISHING THESURFACES OF THE CONTINUOUS STRIP IN THE WELD AREA TO FORM A JOINT HAVINGSMOTH SEALABLE SURFACES AND A THICKNESS SUBSTANTIALLY LESS THEN THECOMBINED THICKNESS OF THE TWO JOINED STRIP MATERIAL, STORING CERTAIN OFTHE CONTINUOUS STRIP TO ASSURE A CONTINUOUS SUPPLY OF STRIP MATERIALDURING THE TIME REQUIRED FOR THE ADDITION OF ANOTHER COIL OF STRIMATERIAL TO THE CONTINUOUS STRIP, PASSING THE STIP THROUGH ANELECTROLYTIC APPARATUS TO CLEAN AND CHARGE THE STRIP WITH HYDROGEN,RINSING THE STRIP, DRYING THE STRIP, PASSING THE STRIP THROUGH A SEALINTO A VACUUM CHAMBER AND MAINTAINING A TENSION ON THE STRIP WHILEWITHIN THE VACUUM CHAMBER TO FACILITATE TRACKING ALONG A PREDETERMINEDPATH WITHIN THE VACUUM, CHAMBER, HEATING THE STRIP TO RMOVE GASES ANDOXIDES FROM THE STRIP, THERMALLY TREATING THE STRIP TO MAINTAIN THESTRIP AT THE DESIRED COATING TEMPERATURE, DEPOSITING METAL ON OPPOSITESURFACES OF THE STRIP FROM SOURCES OF METAL VAPOR BY CONDENSATION OFMETAL VAPOR ON THE MOVING STRIP, PASSING THE STRIP OUT OF THE VACUMCHAMBER THROUGH A SEAL, REWINDING THE COATED STRIP MATERIAL IN COILFORM, TOGETHER WITH THE STORING OF PORTIONS OF THE COATED STRIP MATERIALAS IT PASSES OUT OF THE VACUUM CHAMBER DURING THE REMOVAL OF A COIL ANDFEEDING THE COATED STRIP MATERIAL DURING THE WINDING OF A COIL AT AFASTER RATE THAN THE FEED RATE THROUGH THE VACUUM CHAMBER TOSUBSTANTIALLY DEPLETE THE STORED COATED STRIP MATERIAL, AND THEN CUTTINGOFF THE INDIVIDUAL COIL.